Projection lamp



R. EJMIESSE PROJECTION LAMP Sept. 8, 1931.

Filed Sept.

Patented Sept. 8, 1931 RICARI) E. MIZESSE, OF CHICAGO, ILLINOIS, ASSIGN'OR T0 OF CHICAGO, ILLINOIS, A CORPORATION Q.' B. s. DE vRY CORPORATION, or ILLINOIS U raoJEcmroN LAMP Application led September 24, 1928. Serial No. 308,080.

My invention relates to projection lamps and has for its object the provision of an improved lamp of this character.

' In the preferred embodiment of this invention I utilize a vacuoustube in which two electrodes are provided, one of whichis preferably hollow and the other of which is placed at or near the focus of the hollow electrode. The path of the discharge takes place between these two. electrodes.

I find it desirable., inthe preferred form of the invention, to take auxiliary ionizing means to initially assist in the ionization of this discharge path.

I will describe one form of the invention more in'detail by referring to the accompanying drawing which -illustrates somewhat diagrammatically my invention, certain parts being drawn in section.

In the drawing I show a vacuous tube 1() made of glass or similar lmaterial. I have not thought it necessary to show the base structure for this tube as any suitable form can be used. This glass tube is provided with an in-turned Astem 11 which carries the supports for certa-in instrumentalities. Two instrumentalities which are carried by this base are the electrode 12 and the electrode 13. The electrode 12 consists preferably of a tungsten or tantalum ball about .060-.070 diameter. The electrode 13 is preferably made of molybdenum or tantalum and is preferably shaped in a rounded or parabolic form, thus constituting what I might call a hollow electrode. The electrode V12 is placed substantially at the focus of the hollow electrode 13. A discharge is adapted to -be maintained between these electrodeswhen the device is normally operating. Thel device itself is adapted to be ener zed by the normal 110 volt circuit either a ternating current or direct current.

The electrodes 12 and 13 are connected by lead-in wires 14 and 15 with a suitable source of current 16 as shown ,diagrammaticallv A Stein 17 serves rigidly to hold the electrode 12 in its proper relationship to the electrode 13, a resistance 18 serving to limit the current iow between the electrodes l2 and 13.

Now in order to secure a prompt and effective initial ionization of thepath between the electrodes 12 and 13, I provide auxiliary ion-v small cutaway portion shown herein as the` hole 25, which is directly in the path between the electrode 12 and the filament 19.

The complementary thermal element 23 is rigidly supportedon and electrically connected to the stem 14. When the device is not 4 in operation, the elements 22 and k23 are in contact. The stem 24 has a horizontal porvtion 26 which is made of a metal having a high co-eiiicient of expansion. The elements 22 and'23 are preferably made of silver.- i

Now when the current is initially turned on to the device, a difference of potential is established across the electrodes 12 and 13 and current also passes through the filament 19. The filament is thus heated to incan descence. In the claims I use the words lheating the filament to incandescence,

meaning of course, such heating as is required to cause the emission of electrons. The iilament may be coated with an activating substance, thus lowering the temperature to Which it must be heated in order to bring this oi electrons which tend to travel toward the electrode 12 whereby vthe path between the electrodes 12 and 13 is Y:ionized and-a discharge takes place between these electrodes.

. about. The filament being thus heated throws y After the device has operated a predetermined initial period of time, the element 26 is sufficiently heated so that its expansion will separate the elements 22 and 23 whereupon the current to the Filament is cut out, its ionizing influence no longer being required as the arc once established between the elec? trodes 12 and 13 will continue and maintain itself. The heat ot the device itself is then suiicient to maintain the element 26 in its expanded condition.

One of the main purposes of this projection lamp device is to secure a light of comparatively great candle power concentrated over a very small area. It will be clear from the illustration, that the tungsten ball operating at a white heat generates rays of great actinic power. With the parabolically shaped reiiector behind it, an enormous concentration of light rays can be obtained within a restricted small area.

Such a light would be serviceable for the projection of moving pictures, microscopic examination, stereoscopic slides, tc. Due to the fact that there is a large emanation of ultra-violet and infra-red rays, this device would be useful in conjunction with therapeutic work. The'device is small and can be readily manipulated. A quartz rod, for instance, could beheld against the glass directly in front of the glowing tungsten ball and the other end of the rod directed against the infected areas in the mouth, the throat and in the regions of the soft palate. Other uses will readily suggest themselves.

From what has been thus described, the nature'of my invention will be readily clear to those skilled in the art and it will also be clear that many modifications may be made from the structure herein shown without departing from the spirit of the invention.

AHaving, however, thus described one of its forms, what I claim as new and desire to secure by Letters Patent is:

l. A device of the character described comprising a vacuous.tube, electrodes therein adapted to be the terminals of a discharge, auxiliary ionizing means in said tube to assist in preliminary ionization of said discharge path, and means in said tube adapted after the initial period of said discharge to render said auxiliary ionizing means inoperative, one of said electrodes being provided with a concave parabolic reflecting surface and the other of said electrodes being at substantially the focus of said concave electrode.

2. A device of the character described comprlsing a vacuous tube, electrodes therein adapted to he the terminals of a discharge, auxiliary ionizing means in said tube to assist in preliminary ionization of said discharge path, and means in said tube adapted after the initial period of said discharge to render said auxiliary ionizing means inoperative, one of said electrodes being hollow and having a parabolic shaped interior surface and the other of said electrodes being at substantially the focus of said hollow electrode, said hollow electrode having a cutaway portion in the path extending between the other elec trode and said auxiliary ionizing means.

In witness whereof, I hereunto subscribe my name this 6th day of September A. D.,

RICHARD E. MIESSE.

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